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Author Topic: Why not an FT-891 for portable QRP??  (Read 24750 times)
KF5KCA
Member

Posts: 74




Ignore
« on: July 19, 2017, 11:27:55 AM »

Hello, friendly HAMs  Smiley

You maybe tired of product related questions, but I would like some feedback on why the FT-891 may not be a good choice for field/portable/QRP. I am currently looking at the FT-891, KX2 and FT-817. I am not interested in a discussion as to why is was a bad idea to leave UHF/VHF out when designing the FT-891 as my UHF/VHF needs are met by my trusty VX-5R.

Here some info for my specific situation. I am not trying to mountain climb for days where a couple of pounds make a world of a difference. I am in a world where I was just considering the FT-891 for a mobile installation in my Jeep (which the detachable face plate of the FT-891 would be great for), but now figure that portable maybe more fun. 2 hour hikes (one way) will be my max and an external battery will be part of my pack. I am also not going to engage in CW, which I think is an important factor in this equation.

I like the FT-817, but it is certainly limited to QRP and its technology is from a decade+ ago- not saying this is bad, but there have been some developments in radio communication that the FT-891 and KX2 may bring to the table. Also, the price of the FT-817 is high in comparison at $699.

The KX2 seems great and folks love the receive. What turns me off a little is that it does seem like a kit-radio, even when purchased assembled. There are openings in the chassis galore and sand and/or moisture and dirt can pretty much enter everywhere. I am not a neat freak and things may end up on the bottom of the bag that I had not planned for. Making a small Pelican case part of the deal is probably appropriate, but then takes away from its size advantage. Also, the price is a bit out of line with the others. At ~$750 for the radio and $50 for the mic, we are looking at almost $800 for the KX2. That is a good $100-$150 more than any of the Yaesu radios.

The FT-891 seems very versatile. It is reasonably compact, offers the option to go to 100W if needed (or down to 5W for QRP), has DSP and roofing filter, a large display, a detachable front panel (for possible mobile application) and the lowest price at $630. I am of a younger generation (under 50, so relatively speaking in HAM terms Grin) and menu driven GUIs are no turnoff for me. As a matter of fact, I prefer compact size and well done hierarchical menus to 30 cryptic buttons on the front panel.

So, I am currently failing to see why I should not be going with the FT-891 unless the KX2's RX and TX for SSB are light-years ahead of the FT-891 ($200 worth of light-years to be precise).

As usual, any input is greatly appreciated!

73,

Oliver
KF5KCA
« Last Edit: July 19, 2017, 11:45:07 AM by KF5KCA » Logged
KC4ZGP
Member

Posts: 1637




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« Reply #1 on: July 19, 2017, 12:47:58 PM »


Thanks a lot! You've just convinced me to buy an FT-891.

hi hi

The design looks portable. Make the choice and get one today. $600.00 isn't
a lot of money. If it is, this is not right hobby for you, me or anyone.

I'll be on 17 meters phone this afternoon. I'll give my Alinco SR8T, D-104 and
delta loop some more exercise.

Kraus

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N9AOP
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« Reply #2 on: July 19, 2017, 12:49:32 PM »

Oliver, I have had the FT891 since January.  From April through October I go camping two to three times a month to various parks.  I have a camper so I don't backpack any more.  I used to use a KX3 for camping but I wanted more power on occasion and the ability to do digital without heating up the radio.  I really do not notice any big difference between the 891 and the KX3 I used to have.  Most of my operation is CW.  As far as antennas, it is whatever the location provides.  I prefer wires up a tree but if no close trees I use an Outbacker on an Outreach tripod.  Current draw on RX is 0.8A; 7.6A at 20W; 8.1W at 25W; 10.7W at 50W.  I do have a 20A LiPo (weighs 7 pounds) but I almost always have AC available  so the current draw even at 100W is no problem.  Again, I don't notice any dramatic difference between the KX3 that I had and the FT891 but there is a big difference in the price.  If you get one, it will not break the bank and you will have a lot of fun using it.  At home I have a K3S.
Art
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KF5KCA
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Posts: 74




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« Reply #3 on: July 19, 2017, 12:57:55 PM »


Thanks a lot! You've just convinced me to buy an FT-891.

hi hi

Ha, Kraus!

Yea,when looking at it from a $600 vs $800 perspective it is not a huge deal and I agree that if price were the determining factor, then I should take up bowling. However, I have also come to the point where I have to draw a line somewhere...imagine that. There is an antenna tuner on the menu, a battery, an antenna (hopefully home-grown, but still involves some $$) and on and on we go  Grin

If the KX2 was a slam-dunk out of the gates, I would have no problems forking over the additional $200, but to me it looks like the opposite.

Thanks for the feedback and hope to catch you on the air when I pull the trigger.

Oliver
KF5KCA

« Last Edit: July 19, 2017, 01:08:22 PM by KF5KCA » Logged
KF5KCA
Member

Posts: 74




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« Reply #4 on: July 19, 2017, 01:07:01 PM »

Oliver, I have had the FT891 since January.  From April through October I go camping two to three times a month to various parks.  I have a camper so I don't backpack any more.  I used to use a KX3 for camping but I wanted more power on occasion and the ability to do digital without heating up the radio.  I really do not notice any big difference between the 891 and the KX3 I used to have. [...]

Art,

Thank you for the input! I was especially looking forward to getting feedback from someone who owns an FT-891 and now you have both- great! I am also glad to hear that your experience has not been earth shattering in favor of the KX2 (KX3 in your case). While you are using CW primarily, I believe that CW is actually one of the strong suits of the KX series with the performance gap potentially being even narrower with SSB communication.

I have also read a few articles that stated that the draw of the FT-891 is more along the lines of 0.8A to 1A when in receive only, which is certainly not as good as the FT-817 and does not come close to the KX2, but I would agree that the availability of the extra power outweighs the need for super low power draw. I will chose a battery with sufficient amp/weight ratio to accommodate my needs.

Thank you!

Oliver
KF5KCA

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WB6BYU
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Posts: 17043




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« Reply #5 on: July 19, 2017, 01:13:50 PM »

Many high power rigs work just find at QRP levels, though some better than others.  That gives you the
option for low or high power as the situation requires.

Other than size and weight, the biggest difference for portable operation is the size and weight of the
battery that you have to take along to power the radio.

The most important parameters in this regard are the receive current and the transmit current at the
desired low output power.  The former is included in most specifications:  2A for the FT-891.  The latter
is less commonly specified, and may require someone ho has such a rig to actually measure it for you.
Typically the transmit current will be much higher for the same output power when using a higher
power radio due to the idle current required for high power operation.  At 5W I'd expect a current
draw in the 5 - 8 Amp range.

Probably the most important specification for portable use is receive current (along with minimum
input voltage, which sets how far you can run your battery down and still operate.)  To put the
2A current in perspective, my old HW-8 drew 450mA and my Argonaut 505 drew 1A - at full
transmit output.  My K2 draws about 2A at 10W output, and ~200 mA on receive.

If you want to operate for 2 hours just listening, that will draw 4 Amp-hours, which would be
marginal for a 7Ah lead-gel battery.  If you transmit 30% of the time, then your current
consumption increases to almost 6 Ah.  By contrast, my K2 (at 200mA RX, 2A TX) requires
around 1.5 Ah under the same circumstances, requiring a much smaller battery for the same
operating time.

Now, there are some reviews that say the receive current is closer to 1A with the fan off, and
that would drop the required battery capacity to 4.5 Ah instead of 6.  But you'll still need to
plan to take a large enough battery along.


That's not to say that you can't use the FT-891 for portable use, just that the shortcoming is the
higher current draw - and hence a bigger required battery - than a rig designed for QRP.  If you
only use it occasionally for portable operation for short periods, and don't mind the extra weight,
then it might not be a bad choice.
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KF5KCA
Member

Posts: 74




Ignore
« Reply #6 on: July 19, 2017, 06:47:51 PM »

Many high power rigs work just find at QRP levels, though some better than others.  That gives you the
option for low or high power as the situation requires.

Other than size and weight, the biggest difference for portable operation is the size and weight of the
battery that you have to take along to power the radio. [...]

Dale,

Thank you, I appreciate the detailed feedback. I definitely need to look into the idle current issue that you pointed out. However, given this info and the choices, I would still go for the FT-891 and pack an extra 1 lbs of battery to compensate for the needed power while simultaneously benefiting from having the extra wattage if needed. There are also some technical upsides that still sway me towards the Yaesu.

73,

Oliver
KF5KCA
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VA7CPC
Member

Posts: 2805




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« Reply #7 on: July 19, 2017, 08:11:21 PM »


Art,

Thank you for the input! I was especially looking forward to getting feedback from someone who owns an FT-891 and now you have both- great! I am also glad to hear that your experience has not been earth shattering in favor of the KX2 (KX3 in your case). While you are using CW primarily, I believe that CW is actually one of the strong suits of the KX series with the performance gap potentially being even narrower with SSB communication.

I have also read a few articles that stated that the draw of the FT-891 is more along the lines of 0.8A to 1A when in receive only, which is certainly not as good as the FT-817 and does not come close to the KX2, but I would agree that the availability of the extra power outweighs the need for super low power draw. I will chose a battery with sufficient amp/weight ratio to accommodate my needs.

. . .


Three thoughts:

a) The low "receive" power consumption of the KX3 and FT-817 are significant, if you'll be away from battery-recharging equipment (e.g., a car), or if you're really sensitive to weight.

b) Check the power used for _low-power transmit_ on those rigs.  I bet that the FT-891 uses substantially more power, at 5 watts, than either of the other two radios.  This is caused by bias currents, driver transistor capacity, and so on.

b)  I just received a 3000-mAmpHr Li-Po battery in the mail -- it weighs 10 oz (300 gm) !   So, with new battery technology, you might be OK with the FT-891.

Only _you_ can decide how much weight you're willing to carry, for the _chance_ of transmitting at 100 watts.

.      Charles   (who owns an FT-817 and FT-450).
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KF5KCA
Member

Posts: 74




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« Reply #8 on: July 20, 2017, 10:32:06 AM »


Three thoughts:

a) The low "receive" power consumption of the KX3 and FT-817 are significant, if you'll be away from battery-recharging equipment (e.g., a car), or if you're really sensitive to weight.

b) Check the power used for _low-power transmit_ on those rigs.  I bet that the FT-891 uses substantially more power, at 5 watts, than either of the other two radios.  This is caused by bias currents, driver transistor capacity, and so on.

b)  I just received a 3000-mAmpHr Li-Po battery in the mail -- it weighs 10 oz (300 gm) !   So, with new battery technology, you might be OK with the FT-891.

Only _you_ can decide how much weight you're willing to carry, for the _chance_ of transmitting at 100 watts.

.      Charles   (who owns an FT-817 and FT-450).


Charles,

Thank you that is really good info. I am a bit concerned about the increased receive draw, but the fact that the radio will potentially draw more on 5W TX than a true QRP rig is also concerning.

On the other hand, your are right, batteries have come a long way. There are now LiFePO4 batteries with pretty impressive specs. I just looked at a battery that is not quite as light as the one that you mention ( weighs in at 2.5 lbs), but measures only  4.3 x 3.2 x 3.1 inches and packs a whopping 9 Ah capacity!

Best,

Oliver
KF5KCA
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N2DTS
Member

Posts: 724




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« Reply #9 on: July 20, 2017, 11:21:02 AM »

I had a KX2 and think it was the coolest radio out there.
I plan on getting another and keeping it.

I traded it for an elad, and traded that for a 7300.
I will keep the 7300 and get another KX2.
I also had a KX3 and liked the KX2 a lot better.
The display and ergonomics are very good, its a VERY small radio you can hold in your hand, yet it works so well!
Some things I really liked about the KX2 besides the very small size and light weight:
A very wide range built in antenna tuner,
All modes,
Options like EQ, preamps and built in microphone.
Such a fun radio to use.
You really can put it in your pocket.

I can not imagine an FT anything being as much fun to use.


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KF5KCA
Member

Posts: 74




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« Reply #10 on: July 20, 2017, 02:44:25 PM »

Brett,

I think the real question is: Do you really like the KX2?  Grin

Best,

Oliver
KF5KCA
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K0UA
Member

Posts: 1341




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« Reply #11 on: July 21, 2017, 08:21:46 AM »

Here is my 2 cents on this discussion.  I have used the FT450 as a low power portable rig, but just like any other 100 watt class radio, it is terribly inefficient when set to 5 watts. The bias current it somewhere around 4 amps before any modulation is even applied to the radio.  Do the math, 4 amps x 12 volts means you are putting 48 watts into the radio as heat before a single watt is coming out. So putting out 5 watts you are burning up 5 amps or so of current.  60 watts of input for 5 watts out. Sure it is great to be able to have the extra power on tap when you need it. Sometimes 5 watts just doesn't cut it. But you better have a sufficient battery.

Someone of the big 3 needs to come out with a modern QRP radio to compete with the Elecraft models. at about half the price.

The Icom 7300 has taken the world by storm, and kicked the legs out from under the competition. It is more radio for less money than anything in its class.  Why can't someone come up with a QRP radio to blow away the competition in the same vain as the 7300?
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KF5KCA
Member

Posts: 74




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« Reply #12 on: July 21, 2017, 10:55:45 AM »

Here is my 2 cents on this discussion.  I have used the FT450 as a low power portable rig, but just like any other 100 watt class radio, it is terribly inefficient when set to 5 watts. The bias current it somewhere around 4 amps before any modulation is even applied to the radio.  Do the math, 4 amps x 12 volts means you are putting 48 watts into the radio as heat before a single watt is coming out. So putting out 5 watts you are burning up 5 amps or so of current.  60 watts of input for 5 watts out. [...]

Hm, so you are saying that there will be essentially little to no modulation until you consume ~4A. So, operating at 5W then would be least beneficial. Without wanting to go into a philosophical discussion about what constitutes true QRP, it would then be more beneficial to run this radio at a rate of more than 5W because the efficiency between let's say 5W and 10W would be greater than that between 0-5W in relative terms. Of course, you will consume more current running at 10W, but you will burn the initial 4A regardless of you setting the power to 5W or 10W.

That is indeed interesting as it becomes more of a discussion of doing true portable QRP vs. relatively low power luggable operation. From a weight perspective, it is the difference between carrying ~6.5 LBS (FT-891 + heftier 8Ah battery) or 1.7 LBS (KX2 with a 3Ah external battery). In addition, one could use the internal KX2 battery and have a less efficient, but very compact solution and possibly shave off a few more ounces. And then, if one needed 100W one can just shell out the additional and ridiculous $800 for the Elecraft amp. Not trying to be sarcastic, but it seems that the KX2 would be a dedicated QRP rig unless one goes with a 3rd party amp option.

That leaves me with:

KX2 Pros:
True QRP (efficient for operation <=5W)
Light weight (~1.7 LBS with 3Ah LiFePO4 battery)
Option for internal tuner

KX2 Cons:
Price (~$900 with mic and external LiFePO4 3Ah battery)
Weather-proofing (many openings in case and some complaints about screen cover)
No roofing filter
Limited to <10W (unless adding expensive external amp)


FT-891 Pros:
Price (~$730 with mic and external LiFePO4 8Ah battery)
Better weather-proofing
Built-in roofing filter
Can deliver up to 100W without external amp
Detachable face would make good unit for mobile installation
Could function as base unit

FT-891 Cons:
Not true QRP (not efficient for operation <=5W)
Heavier weight (~6.5 LBS with 8Ah LiFePO4 battery)
No option for internal tuner


The price difference is not all that great after all. We are talking about ~$170 here. What it really comes down to is if I want to carry the extra (almost 5 LBS) pounds and do QRP'ish operation with the option to dial up the wattage, if I need to, or if I want to be truer to the spirit of QRP and have an extremely compact radio but give up the idea of converting it to a mobile or base station one day. If I could convince myself to get into CW the case would be a slam dunk for the KX2. For SSB voice I am still at a bit of a cross-roads....

Thank you all for your good feedback on this!

Best,

Oliver
KF5KCA



« Last Edit: July 21, 2017, 11:06:32 AM by KF5KCA » Logged
KB1GMX
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Posts: 1496




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« Reply #13 on: July 21, 2017, 11:57:18 AM »

First like many I have to point out there are different flavors of portable.

Over the years portable was a almost a dirty word as it meant at most it has a handle.

ALT-1) back in the day....  a portable SSB rig might have been a Tempo-one with 12V DC supply
or SBE34.   In RX mode about 6A, TX oddly about 21A for full output and at lower power ~10W
about 10A.   Easily mobile (for the day!), portable for field day would have needed a genset or
a few 100ah marine batteries.   State of the art back when Heathkit and others ran about the
same.  Most of the power went to the tube heaters.  Back then it meant one person could
emplace it without serious risk of back injury.   I include this as most portable tube radios
were often a CW transmitter in the 1-3W class regen or simple superhet and many pounds
of A,B, and C batteries.

All solid state era:
ALT-2) The radio in my truck is a TS440S/AT 100W heavy and solid, tx SSB no modulation is 3.8A
so any "portable on battery" means something in 33Ah range for some run time likely more like a
60-100ah for a day.  But as Mobile rig it's just fine and mobile is one edge of portable.   Other radios
I've measured may be more compact but the minimum power needs are for 100W class nearly the
same and jump up to the 8A range for ~5W.

Alt-3)  An oddity to many are green radios, old military back pack sets.  They ran from tubes
and sizeable batteries or later transistors.  The one I know best is PRC1099.  Transmitter that
does 5/20W SSB and covers 1.6 to 30mhz portable (30-33pounds with gell cell lighter with lithium)
and has a built in auto tuner that can load most anything.  For outings that are say a day with water
and a meal its portable.  The battery about 10AH runs it for days on RX (140ma) and peaks on tx
are about 4A in the 20W setting.  

ALT-4) I have a FT817, compact and all modes and most if not all bands of any rig.  To run more
than short time external battery is needed either 5AH (11oz weight) or 11AH (21oz weight) LION
do it well with low weight and size.  The latter battery is easily enough for day backpack or moderate
weight for a local hike.  Numbers are it stucks down about 400ma RX and peaks 2A TX.

ALT5) lighter but we give up something.  A KNQ7A 40M (or a homebrew monoband)  both light and
simple and near the extreme lower limit for SSB power needs at a few watts (4-9 watt range).  RX is
around 85ma and tx peaks under 3A.  Small battery and its good at light weight.

ALT-6)  We venture into the ultralight.  CW only radios.  A good example is the 1 Watter
(kitsandparts.com) and many others where you have a monoband  transceiver in the 1-5W class.
Typical power needs for these are small under 50ma RX and 350ma tx (my 1w at 1.1W and 12.7V).
This runs well using a 3 cell (3S1P) Lipo pack using 18650 cells (6oz weight).  This is a pack radio
for several days hike.  The key here is most are kits.  The there are a few CW only radios assembled
out there and are all low power (under 5W) and easy on the battery.

All are portable by some definition but run from barely able to carry (over 75 pounds) down to
under 1.5pounds complete kit.  

Take away items:

 * All 100W radios are terrible for power consumption at low power (5-20W).  The exceptions are few.
 * Most of the 20W and under radios do very well at low power for efficiency.  This is important to get
   most run time from battery.
 * CW only radios are generally very power efficient and also more compact.
 * Many commercial tranceivers do poorly at less than 11 to 11.5V, exceptions are those designed
   for portable work like FT817, many of the kit monobanders and old radios like Argonauts (505, 509,
   others).  This is the most important as even a 100ah marine battery will drop below 12V fairly quickly
   (under TX load) well before its exhausted.

 Portable can be operating from home but not backpackable (a few hours at the park) to something
 that tucks into a hiking pack with two days water, food, and field shelter.  Be specific.

One note: Any means to put power back into the battery (genset, solar, wind, water, human power)
can go far to extending operating time using battery power.   It can help reduce the size of the battery
needed to sustain operation.  The battery still has to be able to support peak power requirements!

Allison

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K0UA
Member

Posts: 1341




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« Reply #14 on: July 21, 2017, 12:16:03 PM »

First like many I have to point out there are different flavors of portable.

Over the years portable was a almost a dirty word as it meant at most it has a handle.

ALT-1) back in the day....  a portable SSB rig might have been a Tempo-one with 12V DC supply
or SBE34.   In RX mode about 6A, TX oddly about 21A for full output and at lower power ~10W
about 10A.   Easily mobile (for the day!), portable for field day would have needed a genset or
a few 100ah marine batteries.   State of the art back when Heathkit and others ran about the
same.  Most of the power went to the tube heaters.  Back then it meant one person could
emplace it without serious risk of back injury.   I include this as most portable tube radios
were often a CW transmitter in the 1-3W class regen or simple superhet and many pounds
of A,B, and C batteries.

All solid state era:
ALT-2) The radio in my truck is a TS440S/AT 100W heavy and solid, tx SSB no modulation is 3.8A
so any "portable on battery" means something in 33Ah range for some run time likely more like a
60-100ah for a day.  But as Mobile rig it's just fine and mobile is one edge of portable.   Other radios
I've measured may be more compact but the minimum power needs are for 100W class nearly the
same and jump up to the 8A range for ~5W.

Alt-3)  An oddity to many are green radios, old military back pack sets.  They ran from tubes
and sizeable batteries or later transistors.  The one I know best is PRC1099.  Transmitter that
does 5/20W SSB and covers 1.6 to 30mhz portable (30-33pounds with gell cell lighter with lithium)
and has a built in auto tuner that can load most anything.  For outings that are say a day with water
and a meal its portable.  The battery about 10AH runs it for days on RX (140ma) and peaks on tx
are about 4A in the 20W setting.  

ALT-4) I have a FT817, compact and all modes and most if not all bands of any rig.  To run more
than short time external battery is needed either 5AH (11oz weight) or 11AH (21oz weight) LION
do it well with low weight and size.  The latter battery is easily enough for day backpack or moderate
weight for a local hike.  Numbers are it stucks down about 400ma RX and peaks 2A TX.

ALT5) lighter but we give up something.  A KNQ7A 40M (or a homebrew monoband)  both light and
simple and near the extreme lower limit for SSB power needs at a few watts (4-9 watt range).  RX is
around 85ma and tx peaks under 3A.  Small battery and its good at light weight.

ALT-6)  We venture into the ultralight.  CW only radios.  A good example is the 1 Watter
(kitsandparts.com) and many others where you have a monoband  transceiver in the 1-5W class.
Typical power needs for these are small under 50ma RX and 350ma tx (my 1w at 1.1W and 12.7V).
This runs well using a 3 cell (3S1P) Lipo pack using 18650 cells (6oz weight).  This is a pack radio
for several days hike.  The key here is most are kits.  The there are a few CW only radios assembled
out there and are all low power (under 5W) and easy on the battery.

All are portable by some definition but run from barely able to carry (over 75 pounds) down to
under 1.5pounds complete kit.  

Take away items:

 * All 100W radios are terrible for power consumption at low power (5-20W).  The exceptions are few.
 * Most of the 20W and under radios do very well at low power for efficiency.  This is important to get
   most run time from battery.
 * CW only radios are generally very power efficient and also more compact.
 * Many commercial tranceivers do poorly at less than 11 to 11.5V, exceptions are those designed
   for portable work like FT817, many of the kit monobanders and old radios like Argonauts (505, 509,
   others).  This is the most important as even a 100ah marine battery will drop below 12V fairly quickly
   (under TX load) well before its exhausted.

 Portable can be operating from home but not backpackable (a few hours at the park) to something
 that tucks into a hiking pack with two days water, food, and field shelter.  Be specific.

One note: Any means to put power back into the battery (genset, solar, wind, water, human power)
can go far to extending operating time using battery power.   It can help reduce the size of the battery
needed to sustain operation.  The battery still has to be able to support peak power requirements!

Allison



A very good analysis.  I think you hit all the points.
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